Extraction of oils



E. E. REID April 28, 931.

EXTRACTION OF OILS Filed sept.4 13, 1928 STILL HEA TING COIL lNvENToR Zelle/fe BY 6D ATTORNEYS Patented Apr. 28, 1931 EBENEZER EHMET REID,

iseasas PATENT OFFICE OF BALTIMORE, MARYLAND, ASSIGNOR TO COLUMBIA ENGINEERING & MANAGEMENT CORPORATION, OF NEW YORK, N. Y., A CORPORA- TION F 00 EXTRACT'ION or oILs Application led September 13, 1928. Serial No. 305,623.

This invention relates to the extraction of fats and oils and oleaginous materials, and particularly to the use of solvents for that purpose.

@ils are usually recovered from seeds and similar vegetable products by crushing them in a press and expressing the oil. The amount of oil which can be separated by that method is naturally limited. A large proportion of the oil is left in the press cake, for example, in the case of cotton seed, about 6.50% of the Weight of the cake or about of the oil recovered by pressing. There is, therefore, a very substantial loss of oil.

Numerous attempts have been made to avoid losses by extracting oils from crushed vegetable materials with the aid of solvents. The solvents employed heretofore 1n commecial operations are liquids such as ga soline or naphtha and include constituents Wlth boiling points Well above ordinary atmospheric temperature at the usual pressure, and often above the maximum temperature `which can be applied safely to the oil. Such solvents are not adapted for the successful recovery of oils for various reasons. The

' solvent or portions thereof cannot be removed completely fromthe oil and from the residue. The presence of even traces of these solvents in the products makes them unsuitable for many purposes. The oil, for example, is not edible, and the residue cannot be employed as cattle food and is suitable for use only as fertilizer. Moreover, the retention of the solvent in the oil and residue involves a direct loss and results in additional expense for fresh solvent. The degradation of the products and the loss of solvent make the operation unprofitable. Consequently, the object of solve-nt extraction is defeated.

It is the object of the present invention to provide an efficient and economical method of recovering oils and fats and oleaginous materials from vegetable products and the like.

I have discovered that the diiiculties hereinbefore mentioned can be overcome readily by utilizing solvents which are gaseous at ordinary atmospheric temperature and presf sure but are liqueiied by a slight reduction in temperature or increase in pressure or by a combination of the lowered temperature and increased pressure. By ordinary atmospheric temperature and pressure I mean the temperature and pressure of the atmosphere as in commercial plants during all seasons of the year. The temperature in particular is subject to variation at different seasons. v The pressure is subject to the usual barometric changes. I prefer to operate under pressures somewhat above atmospheric at or about ordinary atmospheric temperature. |The solvent may be maintained thus in the liquid phase Without substantial cooling, and it can e vaporized and separated readily from the oil and residue by the application of heat.

Among the solvents which are especially ada ted for the process as hereinafter -descri ed are lontaneJ and iso-butano or mixtures thereof. But-ane and iso-butane are gases at ordinary atmospheric temperature and pressure. These gases can be obtained from various sources, among which are natural gases.-

The treatment of casing head gasoline d erived from natural gases yields a proportion of butano and iso-butano which may be utilized for my purpose. Butane is liquefied at ordinary atmospheric temperature by the application of a pressure of 20 pounds gauge. It is readily vaporized by application of heat. The pressures and heat supplied in the system can be adjusted readily to vaporize the solveut When desired and to condense it as liquid.

Other solvents including several hydrocarbon compounds may be used in the method. Thus butylene or iso-butylene, propane, propylene, methyl chlorid and ethyl chlorid have oo l boiling points at ordinary atmospheric pressure and other characteristics which may permit substitution thereof for butane or isobutane. Solvents employed in the process should be free from high boiling-point ends. A

In carrying out the invention I prefer to employ a closed system to avoid loss of the solvent. Thus the apparatus may include an extractor in which oleaginous material is subjected to the solvent in the liquid phase. The solution is delivered to a boiler which may be heated in any suitable Way, for example, by a coil carrying steam or heated Water. The

be distilled in the still l or it may passed through a eat is withdrawn ,pounds per square inch'gauge or higher, de-

pending upon the nature of the solvent. In case butane is the solvent, the pressure may vary within a relatively wide range, for example, with a temperature of F. in the condenser the pressure of the system would' be approximately 30 pounds per square inch gauge, and with a temperature of 60 F. in the condenser the pressure would be. approximately 15 pounds per square inch gauge.

The invention w1ll be better understood by reference to the following description and accompanying drawing, which is a diagrammatic representation of an apparatus adapted for use in practising the invention.

Referring to the drawing, 1 represents a still which is partially filled with the solvent,

` 2 is a condenser adapted to liquefy the solvent vapors, and 3 is an extractor in which the oleaginous material is treated with the solvent. The solvent is vaporized by heat applied through a coil 4 which is supplied with steam or heated water. The vapor is delivered by a pipe 13 to the condenser 2 wherein it is cooled by a cooling medium such as water or air circulating through a coil 5. The condensed solvent passes through a pipe controlled by a-valve 8 into the extractor 3 in which the material to be extracted rests on a diaphragm 6. .A Siphon 7 extending beneath the diaphragm delivers the solvent and the dissolved fat or oil, under control of a valve 9 to the still 1 wherein the solvent is vaporized. The vapor is delivered to the condenser. Fresh solvent may be introduced as required through pipes controlled by valves 10 or 11.

The system is maintained under a suitable pressure as indicated by the pressure gauges 14, and the circulation of the solvent results in an accumulation of dissolved fat or oil in the still. When the extraction is completed the residue in the extractor may be discharged into a suitable heater wherein the residue is heated to drive out any remaining solvent which can be recovered in a suitable condenser and returned to the system. The solution can be withdrawn through a pipe controlled y a valve 12 and subjected in a separate still to distillation. In the latter` case a condenser may be provided to recover the solvent, or the vapors may be delivered to the condenser 2.

The following procedure may be used as anillustration of my method:

Valves 8, 9 and 10 are closed and the sol-y vent (butane) in the liquid state is introduced into the still 1 throu h the valve'12 until the still 1 is partially lled. Valve 12 is then Lacasse closed.y The material from which oil is to be extracted is then introduced into extractor 8 throu h an opening r vided for that purpose -not shown). his material rests on a plermeable membrane 6 through which only uids can pass.

e apparatus is now ready for operation. Valves 8 and 9 are opened and valve 10 is closed. Heat is applied to the solvent in still 1 by means of steam or hot water circulat' in the coil 4. This heat evaporates partui the solvent which condenses in the condenser 2, by means of cold water or air circulated in the `coil 5. The condensed solvent flows down into the extractor 3 and through the material from which oil is to be extracted. When the liquid back to the still 1. Thus we have a con- 5 f tinuous operationin a closed system under pressure as indicated by the gau es 14. With utane, at a temperature of 60 in the condenser, the pressure would beabout 15 lbs. per square in. gauge'.

The process is allowed to continue unti all of the oil has been-removed from the material in extractor 3 and has collected in still 1. .When the extraction has been completed, the valves Sand 9 are closed as soon as possible after the last discharge of the Siphon 7, thus isolating the extractor 3 and preventing an more solvent from entering.

e spent material is then removed and the valve 8 opened. The solvent is then distilled from the solution of solvent and extracted material in still 1, is condensed in condenser 2 and is collected in the empty extractor 3, leavivlgl the oil or extracted material instill 1.

en all of the solvent has been distilled oi, valve 8 is opened, valve 10 opened, and the extracted material is drawn olf through valve 12, the heating medium in the coil 4 having been shut off. Valve 12 is then closed.

The spent meal is removed from the extractor and placed in a separate still, where it is heated to remove last traces of solvent, the vapors entering the condenser 2 through the valve 10 and condensing, the condensate collecting in the condenser and flowing back into the still 1. After all of the solvent has been removed from the spent meal, valve 10 is closed and valve 9 opened to allow the solvent to be run back into the still 1. Valve 9 is then closed, and the apparatus is again ready for another extraction.

The method as described permits the extraction of the material treated with maximum eiciency. The solvent being readily vaporizable at relatively low temperatures canbe separated easily and completely from the recovered fat or oils and likewise from the residue. The products are free, therefore, from noxious residues of the solvent used, and are of high quality comparable'with those recovered by pressing. They are suitable for human consumption or for use as cattle food.

I have described a preferred procedure and a. suitable apparatus for the practice thereof, but various changes can be made depending upon the particular solvent employed in the -method and apparatus without departing from the invention or sacrificing any of the .advantaA es thereof. In the accompanying -claims utane includes iso-butane.

I claim: 1. rIhe method of extracting oleaginous I material which comprises subjecting the mature and pressure conditions which main tain the solvent in the liquid phase while in contact with the material to be extracted, withdrawing the solution and vaporizing the solvent to separate it from the extract.

3. The method of extracting oleaginous materialwhich comprises subjectingthematerial to butane as a solvent, maintaining the solvent in the liquid phase while in contact with the material to be extracted, withdrawing the solution, vaporizing the solvent therefrom condensing the solvent, and returning it to the material to be extracted.

4. The method of extractin oleaginous material which comprises su jecting the material to a hydrocarbon solvent, gaseous at ordinary temperature and pressure, maintaining the solvent in a liquid phase while in contact with the material to be extracted, withdrawing the solution, separately withdrawing the residue and heating the same to e'ect complete removal of the solvent.

5. The method of extracting oleaginous materials which comprises subjecting the material to a saturated hydrocarbon solvent, gaseous at ordinary temperature and pressure, maintaining the solvent in a liquid phase while in contact with the material to be extracted, withdrawing the solution, sepa- -rately withdrawingthe residue andheatingthe same to eiect com lete removal of the solvent.

6. The metho of extracting oleaginous materials which comprises subjecting the material to butane as a solvent, maintaining the solvent in a liquid phase while in contact with the material to be extracted, withdrawing the solution, separately withdrawing the residue and heatmg the same to effect complete removal of the solvent.

7. The method of extracting oleaginous materials which com rises subjecting the material to a hydrocar on solvent, gaseous at ordinary temperature and pressure, maintaining the solvent in the liquid phase while in contact with the material to be extracted, withdrawing the solution, and vaporizing the solvent to separate it from the extract.

8. The method of extracting oleaginous materials which comprises subjecting the material to a saturated hydrocarbon solvent, gaseous at ordinary temperature and pressure, maintaining the solvent in the liquid phase while in contact with the material to be extracted, withdrawing the solution, and vaporizing the solvent to separate it from the extract.

In testimony whereof I aix m signature.

EBENEZER EMME REID. 

